New analytical techniques were developed and used in enzymatic research and in clinical investigations of lipidoses. Gaucher's disease is a lipidosis caused by a deficiency of the lysosomal enzyme, glucocerebrosidase. Significant changes occur in the bone marrow of patients with this disease. In order to understand the biochemical basis of these changes, a study of the lipid components of normal and Gaucher's bone marrow was undertaken. All major phospholipids and neutral lipids were quantitated in four normal and four Gaucher marrow specimens. Triglycerides were found to be the most prevalent lipid in both normal and Gaucher marrow. Additionally, a large difference in the levels of triglycerides was found between the Gaucher specimens and the normal controls. A larger sample of normal (n=8) and Gaucher (n = 16) marrow specimens were analyzed for triglyceride, glucocerebroside and protein content. Triglyceride levels were dramatically reduced in Gaucher bone marrow (51 mg/g wet wgt) in comparison to normal marrow (278 mg/g wet wgt). The level of glucocerebroside was increased in Gaucher marrow (7.1 mg/g wet wgt) relative to normal levels (0.06 mg/g wet wgt), while protein content was not significantly altered by disease. The decrease of total marrow lipid in Gaucher disease in spite of an increase in glucocerebroside explains the decreased fat fraction that is seen in magnetic resonance imaging of the bone marrow in such patients.